Peel and slice the potatoes (or cut into thin slices) spread on the baking sheet, season with salt and pepper. Dice the onions and distribute with the diced ham on the potatoes. Sprinkle everything with grated cheese and bake at 200 degrees in the preheated oven for 20-30 minutes. The flatter the potatoes are on the surface, the crisper they will be.
The cooking time depends on the thickness and quantity of the potatoes.
Homemade guacamole and a fresh salad go well with it.